You want to use a medicine syringe that has ml marking on the size to pull out 25mg of hand lotion It does not have to be exact Would you be way off to assume that mg and ml are about the same?

Mg is a unit of measure for mass, while ml is a unit for volume. They are two totally different things. One ml COULD be equal to mg, but it would depend on what you are trying to measure. You will have to physically measure the mass of one ml of hand lotion.